Richard Angelo drugged patients till they developed severe breathing problems, so that he could heal them and win brownie points with hospital authorities.

Source: Good Samaritan Colorado

2. Benjamin Green

A nurse from UK's Horton General Hospital was a sadist who loved watching people get resuscitated. He loved the thrill of last minute saving so much that he secretly gave them a heavy dose of pain killers, so that they went out of breath.

Source: CreepyPasta Wiki

3. Daniela Poggiali

This Italian nurse is said to have killed up to 96 patients because she found either them or their relatives annoying! She also allegedly took pictures with patients who had just died.

Source: Life News

4. Genene Anne Jones

This American nurse was no ordinary killer. She had a very specialized interest in babies. People started realizing that the babies were dying of causes that were vastly different from what they were admitted for. She is thought to have called around 46 children, but was prosecuted only for 1 Baby Chelsea in the picture above.

Source: Genene Anne Jones

5. Efren Saldivar

Efren Saldivar refers to himself as the Angel of Death and is known for killing elderly patients, by either giving them excess muscle relaxants or decreasing their oxygen intake.
Boy, are we glad we haven't met any